1. Field of the Invention
The present invention relates to an inspection apparatus, an inspection method, and a program.
2. Description of Related Art
In order to measure an accurate three-dimensional shape of a workpiece (inspection target product) by using a photometric stereo principle, there is required an illumination light source whose illumination light is incident on each surface of the workpiece with a uniform light amount. Further, an angle of incidence of the illumination light is required to be known. Moreover, since the angle of incidence of light should not change in accordance with a region of the workpiece, there is required an illumination light source having a size corresponding to the size of the workpiece to be inspected. Furthermore, scale information (actual dimension per pixel) of an image captured by a camera is also required. A visual inspection apparatus is often installed by a user, and it is difficult for the user to satisfy these strict installation conditions. Therefore, according to JP 2007-206797 A, a dedicated apparatus formed by integrating illumination and a camera is proposed, to thereby reduce a burden of installation of the user.
In JP 2007-206797 A, the workpiece 2 is irradiated with parallel light by each of four spot illumination light sources, but a shadow is apt to occur due to the spot illumination. Hence, many regions in the surface of the workpiece are not measurable depending on the type or the placement of workpiece. Such a problem is reduced if an illumination apparatus can be brought away from the workpiece to use regular reflective light, or brought close to the workpiece to use diffused reflective light, in accordance with the type or the placement of the workpiece.
However, in JP 2007-206797 A, since the illumination apparatus and the camera are integrated, arrangement of the illumination apparatus cannot be adjusted in accordance with the type or the placement of the workpiece.